A properly-done step 3 in this mod, with either Focus or Focus-A pads (or in your case, a similar DIY pad), should have the same effect on bass extension / tautness - extension becomes bottomless, and bass gains more tactility / tautness. The intrinsic difference between the two pads set the rest of the bass experience (Focus pads as a basis will give more low-end robustness and rumble, while Focus-A pads will give a slightly leaner, flatter low end).
Regardless, I think proper bass / seal modding on HE560s like this really puts its bass right up against the best of the best; I still stand by my initial statement that from my personal experience this is the best bass I've heard out of headphones.